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Related papers: Minimal conductivity in bilayer graphene

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Using the Kubo formula we develop a general and simple expression for the minimal conductivity in systems described by a two by two Hamiltonian. As an application we derive an analytical expression for the minimal conductivity tensor of…

Mesoscale and Nanoscale Physics · Physics 2012-01-09 Gyula Dávid , Péter Rakyta , László Oroszlány , József Cserti

It is a fact that the minimal conductivity $\sigma_0$ of most graphene samples is larger than the well-established universal value for ideal graphene $4e^2/\pi h$; in particular, larger by a factor $\gtrsim\pi$. Despite intense theoretical…

Mesoscale and Nanoscale Physics · Physics 2012-06-29 J. J. Palacios

Thermodynamic properties of graphene bilayers are studied by path-integral molecular dynamics (PIMD) simulations, considering quantization of vibrational modes and anharmonic effects. Bilayer graphene has been studied at temperatures…

Materials Science · Physics 2020-01-10 Carlos P. Herrero , Rafael Ramirez

We have investigated electrical transport and shot noise in graphene field effect devices. In large width over length ratio $W/L$ graphene strips, we have measured shot noise at low frequency ($f$ = 600--850 MHz) in the temperature range of…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 R. Danneau , F. Wu , M. F. Craciun , S. Russo , M. Y. Tomi , J. Salmilehto , A. F. Morpurgo , P. J. Hakonen

A Drude-Boltzmann theory is used to calculate the transport properties of bilayer graphene. We find that for typical carrier densities accessible in graphene experiments, the dominant scattering mechanism is overscreened Coulomb impurities…

Mesoscale and Nanoscale Physics · Physics 2008-03-22 Shaffique Adam , S. Das Sarma

We have surveyed the in-plane transport properties of the graphene twist bilayer using (i) a low-energy effective Hamiltonian for the underlying electronic structure, (ii) an isotropic elastic phonon model, and (iii) the linear Boltzmann…

Mesoscale and Nanoscale Physics · Physics 2016-12-21 N. Ray , M. Fleischmann , D. Weckbecker , S. Sharma , O. Pankratov , S. Shallcross

We study conductance across a twisted bilayer graphene coupled to single-layer graphene leads in two setups: a flake of graphene on top of an infinite graphene ribbon and two overlapping semi-infinite graphene ribbons. We find conductance…

Mesoscale and Nanoscale Physics · Physics 2020-07-30 Hadi Z. Olyaei , Bruno Amorim , Pedro Ribeiro , Eduardo V. Castro

We numerically calculate the optical conductivity of twisted graphene bilayers within the continuum model. To obtain the imaginary part, we employ the regularized Kramers-Kronig relation allowing us to discuss arbitrary twist angles,…

Mesoscale and Nanoscale Physics · Physics 2013-12-03 Tobias Stauber , Pablo San-Jose , Luis Brey

The electrical conductivity of graphene containing point defects is studied within the binary alloy model in its dependence on the Fermi level position at the zero temperature. It is found that the minimal conductivity value does not have a…

Disordered Systems and Neural Networks · Physics 2015-05-18 Yuriy V. Skrypnyk , Vadim M. Loktev

It has been recently demonstrated experimentally that graphene, or single-layer carbon, is a gapless semiconductor with massless Dirac energy spectrum. A finite conductivity per channel of order of $e^{2}/h$ in the limit of zero temperature…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 M. I. Katsnelson

Many of the experiments in twisted bilayer graphene (TBG) differ from each other in terms of the details of their phase diagrams. Few controllable aspects aside, this discrepancy is largely believed to be arising from the presence of a…

Mesoscale and Nanoscale Physics · Physics 2020-09-30 Bikash Padhi , Apoorv Tiwari , Titus Neupert , Shinsei Ryu

We present exact results for the electronic transport properties of graphene sheets connected to two metallic electrodes. Our results, obtained by transfer-matrix methods, are valid for all sheet widths and lengths. In the limit of large…

Mesoscale and Nanoscale Physics · Physics 2015-06-03 Shijie Hu , Wei Du , Guiping Zhang , Miao Gao , Zhong-Yi Lu , Xiaoqun Wang

We have studied temperature dependences of electron transport in graphene and its bilayer and found extremely low electron-phonon scattering rates that set the fundamental limit on possible charge carrier mobilities at room temperature. Our…

Mesoscale and Nanoscale Physics · Physics 2008-01-07 S. V. Morozov , K. S. Novoselov , M. I. Katsnelson , F. Schedin , D. C. Elias , J. A. Jaszczak , A. K. Geim

We calculate the Fermi energy dependence of the (time-averaged) current and shot noise in an impurity-free carbon bilayer (length $L\ll$ width $W$), and compare with known results for a monolayer. At the Dirac point of charge neutrality,…

Mesoscale and Nanoscale Physics · Physics 2007-05-23 I. Snyman , C. W. J. Beenakker

Highly-doped graphene samples show the conductance reduced and the shot-noise power enhanced compared to standard ballistic systems in two-dimensional electron gas. These features can be understood within a model assuming incoherent…

Mesoscale and Nanoscale Physics · Physics 2024-06-25 Adam Rycerz , Katarzyna Rycerz , Piotr Witkowski

Using calculations from first principles we have investigated the lattice thermal conductivity of ideal mono- and bi-layer graphene sheets. Our results demonstrate that the intrinsic thermal conductivity of both mono- and bi-layer graphene…

Materials Science · Physics 2009-02-05 B. D. Kong , S. Paul , M. Buongiorno Nardelli , K. W. Kim

Electron transport in bilayer graphene is studied by using a first principles analysis and theMonte Carlo simulation under conditions relevant to potential applications. While the intrinsic properties are found to be much less desirable in…

Mesoscale and Nanoscale Physics · Physics 2015-05-30 X. Li , K. M. Borysenko , M. Buongiorno Nardelli , K. W. Kim

Using terahertz time-domain spectroscopy, the real part of optical conductivity [$\sigma_{1}(\omega)$] of twisted bilayer graphene was obtained at different temperatures (10 -- 300 K) in the frequency range 0.3 -- 3 THz. On top of a…

According to electronic structure theory, bilayer graphene is expected to have anomalous electronic properties when it has long-period moir\'e patterns produced by small misalignments between its individual layer honeycomb lattices. We have…

The current and the shot noise in a graphene sheet were analyzed in the ballistic regime for arbitrary voltage drops between leads and the sheet in the limit of infinite aspect ratio of the sheet width to its length, when quantization of…

Mesoscale and Nanoscale Physics · Physics 2009-11-13 E. B. Sonin